Plate clamp for rotary printing presses



- Feb. 13, 1940. w, v, 955 AL 1 2,190,385

PLATE CLAMP FOR ROTARY PRINTING PRESSES Filed Feb. 4, 1939 I k W ill/1mPatented Feb. 13,1940

PLATE CLAMP FOR. ROTARY. PRINTING 'William P. v. Russ" and Donald n.M;r'sj,. time Creek, Mich, assignors to Duplex Printing. Press Company,Battle Creek, Micln, a corporation of Michigan Application February 41939,,S erial N 254 ,713 21 Claims. -m 8 M This'invention relates torotary cylinder printing. presses, and more particularly to 'novelvimprovements in the clamps for securing the printing plates ontothe'plate holding cylinders; c which plates are ordinarily formed withan internal curvature conforming with the" external curvature of thecylinder, the ends of the plates being'beveled and engaged bythe clampswhich are mounted on the cylinden'the clamps having 10 their platecontacting portions undercut so as to overlap the beveled ends of theplates,thereby fixedly holding the plates onthe cylinders against.

radial or axial movements.

It is very desirable and advantageous to mount the'plate clamps at theends of the cylinder so that same maybe retracted below the'surface ofthe cylinder to facilitate placing the plates thereon; and in pressesusing tubular plates, i. e., plates which extend more than half wayaround the cylinder, such mounting is a necessity since in order to slipthe plate onto the cylinder from the end there can be no obstructionextending beyond the surface of the cylindenwhich surface as abovestated conforms with the internal curva-' ture of the plate.

The principal object of ourinvention is to provide a simple, novel, andeiiicient plate clamp having actuating means which will: impart acombined rocking motion and rectilinear motion 30? to the clamp, wherebythe clamp may be retracted to or slightly below the suriaceof thecylinder to' permit a plate to he slipped over the end of the cylinderwithout obstruction, and whereby the'clamp may be projected so as toextend above a the surface of the cylinder to engage the beveled end ofthe plate adjusted on the cylinder proper printing position.

We will explain the invention with reference to the accompanying drawingwhich illustrates 40 one practical embodiment thereof to enable, othersfamiliar with thevart to adopt anduse, the

same; and will summarize in theclaims, the novelfeatures ofconstruction, and novel com-- blnations of parts, for which protectionis desired.

In said drawing:

Fig. lis a partial longitudinal'section through the lock-up end of aplate cylinder,showing one of our novel clamps projected into plateholding position.

Fig.2 is a section on the line 2-2, Fig.1.

Fig. 31s a section similar to Fig. 1 but showing the clamp in "retractedposition; substantially flush with the surface of the cylinder.

Fig.4 is a transverse section through ll of the cylinder in which theclamp operates.

into

the groove Fig; 5 is a-perspective view of'the clamp de-- tached,showing in exploded arrangement the shoes and spring of the frictionmeans.

(Visa f 'ont'view'of the crosshead which actuatestheclamgi'.

Fig. 7' is afside view of the crosshead.

f Aslsliown' in Figs-14, the"body of the plate cylinder lis providedwith recesses, one of which is shown at Z-Qsaid recess being disposedadjacentone'Qendof-Tthejcylinder to nausea plate clamp 3. \Vhilev'vehave illustrated only one clamp- 3 on the'cylinder I there may be anynumberof such clamps arranged around' 'th'e cylinder. Groove 2"ispreferably ofrectangular cross-section, and

at the outer 'edges ofthe sidewalls thereofare opp'osed flanges 2aforming shoulders 2b for the purpose hereinafter set forth. The printingplate is *slidably mounted on the cylinder l,- overlapping fa portionof-groove 2, and. has'its edge v beveled as at P in the usual vmanner.

Mounted on the" ylin'der lgis a ring 4 closing the outer end'o'f recess2, said ring'having a bore in forming a bearing for one end 5a ofa'screw 5 disposedaxially of the 'groove 2, the inner end 51) of thescrew being journaled in a bore 6 in the inner end of said recess. freeto rotate in the recess but is held against axial movement loy' ashoulder 5c thereon engaging the inner face of ring 4. The outer end ofscrewfi projects beyond the ring 4 and is squaredas at 55 or otherwiseformed topermit the screw to'b e rotated by any desired means.

Clamp v 3' is-preferab ly of; inverted "U-shape, and of less length thanthe distance from the plates]? to'thelring 4, and the legs 3ulthereof'are' sp'aced apart""a distance greater than the diameter of screw'5, andthe outer faces of the legs 31; slidably engage the side walls of recess2 as .shown in "Fig.2; The outer upper sides of the clamp 3 are recessedas at 3b. (Fig.5) to conform with the spacing of the opposed faces ofthe flanges 20!. ofrece'ss 2 so that the upper portionof clamp '3 may bepartly projected out of the recess 2 as shown in Fig. 1, in orderthatthe notched inner end 30 of the clamp may embrace the beveled end Pf ofthe plate P and The screw ,5 is

bottom'face of the'pla'te adjacent the bevel P,

the notch 30 conforming with the angularity thereof. Thecl'arnp3 may beretracted entirely within the recess 2 as shown in Fig. 3 or may beprojected lntdplate clamping position, as in Fig. l, and the depthofftherecessed portions 3b of clamp 3 is'such thatwhen the clamp 3 is thusprojected the, shoulders 311;, at the lower ends of theportionstbsquarely contact the shoulders 2b.

, (Fig. 5) in the legs 3a of the clamp, the notches to limit theprojecting movement of the clamp.

When the clamp 3 is projected, the top surface is flush with the outersurface of cylinder I I and forms a support'for' the under: surface ofthe end of the plate Thus the projected clamp 3 fills the gap under theend of the plate formed by the recess 2 in the cylinder.

Threaded on screw 5, within recess 2 ,-is a crosshead 1 (Figs. 6-7) ofsuch width that it will make a sliding fit between the legs 3a. of clamp3, and said crosshead is provided at'its' endswithopposed gudgeons 1aadapted to enter opposed notches =3e Sebeing of slightly greater widththan the diameter of the gudgeons, and the: notches; holding thecrosshead against rotation with the screw 5. However, any other desiredmeans to actuate the crosshead- I axially of the recess 2 may be usedinstead of the screws 5.

The clamp 3 is provided-with a bore-3ficlisposed parallel with and abovetheaxis ofthe notches-3e; In the ends of said bore are placed shoes 8,with a spring 9 interposed between them and yieldably urging the' shoes-8 outwardly into frictional contact against the opposed surfaces of theflanges 2a'of recess 2zas-shown-i-n Fig.2.

In retracting clamp 3 from its plate holding position, shown in Fig. 1,the-screw 5 is rotated to move crosshead 1 away from the plate P. Thegudgeons 1a of the crosshead. engage the clamp through notches 3e andthefrictionalcontact of shoes8 against flanges 212-015 the recessforms acouple. acting to rock the clamp around the movable fulcrum consistingof the-yieldably pressed shoes 8 asthe crossheacland clamp slide inrecess 2, and thus the clamp moves axially in the recess and issimultaneously rocked. When .the clamp has been rocked. to bring itsupper surface at. or slightly below thecylinder surface as shown in.Fig. 3, its plate contacting notch'3c has been movedoutwardly-sufliciently to. clear the end P of the. plate whichcan thenbe removed. over the retracted clamp and withdrawn fromthe cylinder I. Q

'When a plate. R is manuallyplacedon cylinder Iinto, properprintingposition, the above action isreversed to lock the. plate thereon. "Whenthe screw 5 is rotated the clamp is shifted by crosshead ltowards the.plate P, and simultaneously the frictional contact OfIshoes-Ragainst thesides 2a of the recess willfforma couple which will cause the notchedendl3c of the c1amp'3 to rise above. the surface of thecylinder I. =Whenthe clamp. 3 has reached. theendofplate P further movement of thecrosshead I merely shifts clamp 3 inwardly of the. recess, the frictionshoes: 8 merely sliding against the surfaces 2aof the recess,- the clamp3 being held against further rocking movement by the-shoulders 2b on therecess contacting the shoulders 312 on. the clamp;

We claim: I I

'1.v In. combination with a, plate cylinder having a recess, a clamphaving .a plate engaging portion, said clamp being normally housedwithin the recess and slidably mounted therein; means engaging the clampfor moving same axiallyof the recess; and means whereby as the clamp ismoved in one direction the clampwill be rocked in a plane parallel withthe axis of the cylinder to partly,projectsameoutof the recess, and whenthe clamp is moved inytheiother direction the clampwillbe retractedwithin'i the recess.

ring portion out of and into the recess according to the direction ofmovement of the clamp,jcom- -prising opposed shoes slidably andyieldably'erbv couple with the moving means.

- the recess and slidably mounted therein; 'me'ans at the undersides ofthe flanges 2a of recess 2 2. In a combination'as set forth in claim 1,a means for limiting. the projecting movement of? the clamp.

3. In combination with a plate cylinder having," a recess; a clamphaving a plate engaging por- 5 tion, said clamp being normally housedwithin the recess and slidably mounted therein; -meansen gaging saidclamp for moving same axially of the recess; and means for projectingthe plate engaggaging-the sides of the recess and forming a 4.1m acombination as set forth in claim means for limiting the projectingmovement of the clamp.

5. In combination with a platecylinder having I a recess, a clamp havinga plate engaging portion, said clamp being normally housed withinengaging the clamp for moving same axially of the recess; and frictionmeans on the clamp engaging the sides of the recess above the movingmeans and forming a moving fulcrum, whereby as the; clamp is moved; inone direction the said means will rock the clamp to partly project sameout of! a I the. recess, and when the clamp is moved in the otherdirection the saidmeans will retract the clamp within the recess. 30:

6. In a combination as set forth in'claim 5,} v

means for limiting theprojecti-ng action of the said rocking means.

7. In a combination asset forth in claim-.5,

said friction means comprising opposed shoes t fii slidably and.yieldably engaging-the sides of the recess and forming a couple with themoving means tending toupend the clamp. Y

,8.'In combination with a plate cylinder having a recess, a rotatablescrew extending into-" i said recess, a crosshead threaded on saidscrew; a plate clamp having a plate engaging portion, said clamp beingnormally housed within the re: cess and 'slidably mounted therein; saidcrosshead being pivotally connected with said and means whereby as thescrew is rotated in-one direction the clamp will be rocked to partly project same out of the recess, andiwhen' the screw, is rotated in theother direction the clamp'willf be retracted within the recess. 9."In acombination as s'etio'rth in claim 8, means for limiting. the projectingmovementlof, the clamp. I v 10.'In a combination as set forth in cIaimB, said recess having parallelside wallsgand said clamp beingofsubstantially inverted .U-shape}, and having opposed notches in its legsreceiving the ends of the crosshead. .11.In a combination as set'forthin claim'8',';- said rocking means comprising opposedfshoes.slidably and yieldably engaging the sides of the recess and forming acouple with the moving means tendingto upend the clamp. v l2.'In acombination as set forth in claim 8, said clamp havinga bore above and,parallel with the crosshead; said rocking means comprising shoesslidably mounted in the ends of the bore and engaging the sides of therecess, and yield: able within the bore tending to separate the] shoes.I

13. In combination with a plate cylinder hav-- ing a recess, a rotatablescrew extendingfinto said v recess, a crosshead threaded on said screw;.a f 7 recess.

.screw is rotated in the other direction the friction means will retractthe clamp within the 14. In a combination as set forth in claim 13,interengaging surfaces on the walls of saidrecess and said clamp adaptedto limit the projecting action of the friction means. I l I 15. In acombination as set forth in claim 13, said recess having parallel sidewalls,,and said clamp being of substantially inverted -U-shape, andhaving opposed notches in its legs receiving the ends of the crosshead.

16. In a combination as set forth in claim 13, said friction meanscomprising opposed shoes slidably and yieldably engaging the sides ofthe recess and forming a couple with the moving means tending to upendthe clamp. 7

17. In combination with a plate cylinder having a recess having parallelside posed flanges at theouter edgesof saidwalls, a rotatable screwextending into said recess, a crosshead threaded on said screw; a plateclamp having a plate engaging portion, said clamp being within therecess and slidably normally housed mounted therein; engaging saidfriction means posed faces of and forming a whereby as the screw saidcrosshead having its ends the flanges above the crosshead fulcrummovable with the clamp, is rotated in one direction walls and op- 7 saidclamp being of clamp intermediate itsends; and and having opposednotches in its legs on the clamp engaging the opthe friction means willrock the clamp to partly project same out of the recess, and when thescrew is rotated in the other direction the fricvtion means will retractthe clamp within the recess.

18. In a combination as set forth in claim 1'7, said clamp having a boreabove and parallel with the crosshead; and said friction meanscomprising shoes slidably mounted in the ends of the bore and engagingthe flanges, and a coiled spring it.

, within the bore between the shoes yieldabl'y separating the shoes.

19. In a combination as set forth in claim 1'7, said clamp having sidewalls engaging those of the recess, and having inclined surfaces at thet the side walls adapted to engage the clamp is upper ends of theundersides of the flanges when in projected position to limit theprojecting movement of the clamp.

20. In a combination as set forth in claim 17,

said clamp having side walls engaging those of the recess, and havinginclined surfaces at the upper ends of the side walls adapted to engagethe under-sides of the flanges when the clamp is in projected position;said clamp having a bore above and parallel with the axis of thecrosshead; and said friction means comprising shoes slidably mounted inthe ends of the bore and engaging the opposed faces of the flanges; andyieldable' means within the bore tending to separate the shoes.

21. In a combination as set forth in claim 1'7,

substantially inverted U- WILLIAM P. v. Ross.

. DONALD H. MARS.

